Desirable attributes of
species used in small
scale aquaculture
- Protocol

Species commonly used
for aquaculture in
sub-Saharan Africa:
-O. andersonii
-O. aureus
-O. macrochir
-O. mossambicus
-O. niloticus
-O. shiranus
-Tilipia rendalli
-T. zillii
-Clarias gariepinus
-Cyprinus carpio
-Chrysicthys nigrodigitatus
-Heterotis niloticus
-Production of all-male
cichlid offspring

Alien species in African aquaculture
-Enviromental and economic
impacts
-FAO Codes of Practice

The production of all-male cichlid offspring

Three methods are commonly used to produce an all-male population:

  • Hybridisation of two closely related species to produce sterile, all-male offspring: Examples include the following hybrids:
    Oreochromis niloticus females x O. hornorum males;
    O. niloticus x O. urolepis hornorum
    S. galilaeus x O. niloticus
    S. galilaeus x O. aureus
    S. galilaeus x O. mossambicus
  • Hand sexing of fish which involves the discarding of all females.
  • Hormone-induced, sex change
  • Production of a YY "supermale" as a result of sex reversal and/or hybridisation.

None of the above methods is completely successful, and it is common to find up to 10% contamination with females. This can seriously affect production, as illustrated by results of experiments in which varying percentages of female O. niloticus were introduced into the all-male population of (Oreochromis niloticus females X O. hornorum male) hybrids.

References: Fishelson (1987); Lovshin et al 1990;

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